In 1999, Molodtsov [1] introduced the concept of soft sets. In 2003, Maji et al. [2] presented a detailed theoretical study of soft sets which includes soft subset of a soft set, equality of soft sets and operations on soft sets such as union and intersection. In 2009, Ali et al. [3] studied and discussed the basic properties of these operations and defined some new operations in soft set theory as restricted soft intersection, restricted soft union and extended soft intersection. In this paper, we have introduced new concepts of soft sets: restrict of soft set, extent of soft set and mutual soft sets and studied some relations between them and operations on soft sets